The Laboratory for Reactor Physics and System Behaviour (at EPFL and PSI , Switzerland) has in recent years been developing a code system for reactor analysis based on the OpenFOAM numerical library. The main objective is to supplement available legacy codes with modern tools employing contemporary techniques in the fields of software engineering and computational analysis. In particular, the research project aims to step beyond currently available tools by providing high flexibility in terms of physical and geometrical complexity of the problems to solve, high performances in terms of parallel computing, and the possibility to easily tailor the source code based on the needs of each user.

This presentation will offer an overview of how OpenFOAM has been used to achieve these objectives. Some of the developed single-physics solvers will first be presented. Attention will then be focused on the coupling of single-physics solvers into an implicitly-coupled non-linear-consistent multi-physics solver for the transient analysis of nuclear reactors. This solver couples together a multi-scale fine/coarse mesh sub-solver for thermal-hydraulics, a multi-group diffusion sub-solver for neutronics, a displacement-based sub-solver for thermal-mechanics and a finite-difference model for the temperature field in the fuel. It is targeted towards the analysis of pin-based reactors (e.g., liquid metal fast reactors or light water reactors) or homogeneous reactors (e.g., fast-spectrum molten salt reactors).